Film-forming method, manufacturing method of electronic device, and plasma atomic layer deposition apparatus

ABSTRACT

In a film-forming technology using charged particles, a disturbance in film thickness distribution caused by leakage magnetic field is suppressed. A film-forming method embodies a technological idea of switching generation and stop of a magnetic field during a film-forming operation so as to stop the generation of the magnetic field during a period when plasma is generated and generate the magnetic field during a period when plasma is not generated.

TECHNICAL FIELD

The present invention relates to a film-forming technology, amanufacturing technology of an electronic device, and a plasma atomiclayer deposition apparatus, and relates to, for example, a technologyeffectively applied when forming a protection film that protects anorganic EL (Electro-Luminescence) film.

BACKGROUND ART

Japanese Patent Application Laid-Open Publication No. H11-158605 (PatentDocument 1) describes a technology in which, in a state where anelectromagnet incorporated in a mask adsorber is excited to adsorb amask to the mask adsorber, the mask is aligned with a substrate, andthen the electromagnet is returned to a non-excited state and the maskis adsorbed to a surface of the substrate with a permanent magnet.

Japanese Patent Application Laid-Open Publication No. 2008-75128 (PatentDocument 2) describes a technology of forming a film with lessdisturbance in film thickness distribution by preventing a magneticfield from leaking to a film-forming space when forming a film by thesputtering method, the plasma CVD method, or the evaporation methodusing charged particles.

Japanese Patent Application Laid-Open Publication No. 2014-3135 (PatentDocument 3) describes a technology of changing an interval between amask and a substrate by adjusting the magnitude of the current suppliedfrom a current supply unit to an electromagnet.

RELATED ART DOCUMENTS Patent Documents

Patent Document 1: Japanese Patent Application Laid-Open Publication No.H11-158605

Patent Document 2: Japanese Patent Application Laid-Open Publication No.2008-75128

Patent Document 3: Japanese Patent Application Laid-Open Publication No.2014-3135

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

For example, for suppressing a film from being formed in a gap between amask and a substrate, a technology of improving an adhesion between themask and the substrate has been desired. In this respect, a technologyof improving the adhesion between the mask and the substrate byattracting the mask by magnetic force in the configuration in which themask is made of a ferromagnetic substance and a magnetic fieldgenerating unit is provided on an opposite side of the mask with asubstrate interposed therebetween has been studied.

However, this technology is directed to a film-forming method usinguncharged particles typified by, for example, the resistance heatingevaporation method. Therefore, when this technology is applied to afilm-forming method using charged particles typified by, for example,the sputtering method, the plasma CVD (Chemical Vapor Deposition) methodand the plasma ALD (Atomic Layer Deposition) method, the Lorentz forcecaused by the leakage magnetic field acts on the charged particles, sothat a problem of disturbance in film thickness distribution arises. Inother words, when the magnetic force is used to improve the adhesionbetween the mask and the substrate in the film-forming method usingcharged particles, the charged particles are adversely affected by theleakage magnetic field, so that the contrivance to eliminate the adverseeffect of the leakage magnetic field is required.

The other problems and novel characteristics will be apparent from thedescription of this specification and the accompanying drawings.

Means for Solving the Problems

A film-forming method according to an embodiment embodies atechnological idea of switching the generation and stop of the magneticfield during the film-forming operation so that the generation of themagnetic field is stopped in a period when plasma is generated and themagnetic field is generated in a period when plasma is not generated.

Effects of the Invention

According to an embodiment, it is possible to suppress the disturbancein film thickness distribution due to the leakage magnetic field in thefilm-forming technology using charged particles. As a result, it ispossible to improve the film-forming characteristics by the film-formingtechnology according to the embodiment.

BRIEF DESCRIPTIONS OF THE DRAWINGS

FIG. 1 is a plan view showing a mobile phone (smartphone) seen from afront side;

FIG. 2 is a plan view schematically showing a layout configurationformed in a partial region of a display unit;

FIG. 3 is a cross-sectional view taken along a line A-A of FIG. 2;

FIG. 4 is a flowchart showing a manufacturing process of the displayunit;

FIG. 5 is a diagram schematically showing a configuration example ofelectrically connecting the display unit and a circuit unit;

FIG. 6 is a diagram showing a state in which a mask is disposed over aglass substrate;

FIG. 7(a) is a cross-sectional view showing a state of forming a thinprotection film over a glass substrate having a foreign particle adheredthereto by the CVD method, and FIG. 7(b) is a cross-sectional viewshowing a state of forming a thick protection film over a glasssubstrate having a foreign particle adhered thereto by the CVD method;

FIG. 8 is a cross-sectional view showing a state of forming a thinprotection film over a glass substrate having a foreign particle adheredthereto by the ALD method;

FIG. 9 is a diagram schematically showing a state in which a flexiblesubstrate is used as a substrate of a display unit and this flexiblesubstrate is bent;

FIG. 10 is a flowchart for describing a forming method of a protectionfilm by the plasma atomic layer deposition method;

FIG. 11 is a schematic diagram showing a state in which source gas isintroduced into a process chamber of a plasma atomic layer depositionapparatus in a related technology 1;

FIG. 12 is a schematic diagram showing a state in which purge gas isintroduced into the process chamber of the plasma atomic layerdeposition apparatus in the related technology 1;

FIG. 13 is a schematic diagram showing a state in which reaction gas isintroduced into the process chamber of the plasma atomic layerdeposition apparatus in the related technology 1;

FIG. 14 is a schematic diagram showing a state in which plasma isgenerated in the process chamber of the plasma atomic layer depositionapparatus in the related technology 1;

FIG. 15 is a schematic diagram showing a state in which purge gas isintroduced into the process chamber of the plasma atomic layerdeposition apparatus in the related technology 1;

FIG. 16 is a diagram schematically showing a state in which a protectionfilm is formed so as to enter a minute gap between a glass substrate anda mask;

FIG. 17 is a graph showing a relationship between a distance of entrancefrom a mask edge toward the mask and a thickness of the formedprotection film in the related technology 1;

FIG. 18 is a schematic diagram showing a state in which source gas isintroduced into a process chamber of a plasma atomic layer depositionapparatus in a related technology 2;

FIG. 19 is a schematic diagram showing a state in which purge gas isintroduced into the process chamber of the plasma atomic layerdeposition apparatus in the related technology 2;

FIG. 20 is a schematic diagram showing a state in which reaction gas isintroduced into the process chamber of the plasma atomic layerdeposition apparatus in the related technology 2;

FIG. 21 is a schematic diagram showing a state in which plasma isgenerated in the process chamber of the plasma atomic layer depositionapparatus in the related technology 2;

FIG. 22 is a schematic diagram showing a state in which purge gas isintroduced into the process chamber of the plasma atomic layerdeposition apparatus in the related technology 2;

FIG. 23 is a diagram showing a schematic configuration in a processchamber of a plasma atomic layer deposition apparatus according to anembodiment and a state in which source gas is introduced into theprocess chamber;

FIG. 24 is a schematic diagram showing a state in which purge gas isintroduced into the process chamber of the plasma atomic layerdeposition apparatus according to the embodiment;

FIG. 25 is a schematic diagram showing a state in which reaction gas isintroduced into the process chamber of the plasma atomic layerdeposition apparatus according to the embodiment;

FIG. 26 is a schematic diagram showing a state in which plasma isgenerated in the process chamber of the plasma atomic layer depositionapparatus according to the embodiment;

FIG. 27 is a schematic diagram showing a state in which purge gas isintroduced into the process chamber of the plasma atomic layerdeposition apparatus according to the embodiment;

FIG. 28 is a diagram schematically showing points A to H which aremeasurement points; and

FIG. 29 is a graph showing measurement results of the film thickness ofthe protection film at the measurement points indicated by the points Ato H of FIG. 28.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The same components are denoted by the same reference charactersthroughout the drawings for describing the embodiments, and therepetitive description thereof will be omitted. Note that hatching maybe applied in some cases even in a plan view for easy understanding.

<Configuration of Display Unit of Mobile Phone>

FIG. 1 is a plan view showing a mobile phone (smartphone) MP seen from afront side. As shown in FIG. 1, the mobile phone MP according to thisembodiment has a substantially rectangular shape and a display unit DUfor displaying an image is provided on a front side of the mobile phoneMP. For example, the display unit DU according to this embodiment is anorganic EL display unit (organic Electro-Luminescence display unit)using an organic EL element. Also, though not shown, the mobile phone MPincludes a circuit unit for driving the display unit DU.

In the display unit DU, a plurality of pixels are arranged in an array,which makes it possible to display an image. Various circuits are formedas appropriate in the circuit unit. For example, the circuit unit isconfigured to include a driving circuit electrically connected to eachof the plurality of pixels constituting the display unit DU, and thedriving circuit is configured to be able to display an image on thedisplay unit DU by controlling the plurality of pixels constituting thedisplay unit DU.

Next, FIG. 2 is a plan view schematically showing a layout configurationformed in a region RA which is a partial region of the display unit DU.As shown in FIG. 2, in the region RA, for example, lower electrodelayers ELB each extending in an x direction are arranged in a ydirection so as to be separated from each other, and upper electrodelayers ELA each extending in the y direction are arranged in the xdirection so as to be separated from each other. Therefore, in theregion RA, the lower electrode layers ELB and the upper electrode layersELA are laid out so as to intersect with each other.

Next, FIG. 3 is a cross-sectional view taken along a line A-A of FIG. 2.As shown in FIG. 3, for example, a passivation film PAS is formed over aglass substrate GS having translucency to visible light. The passivationfilm PAS is made of an insulating material (insulating film), forexample, a silicon oxide film. Although the passivation film PAS may notbe formed over the glass substrate GS in some cases, it is moredesirable to form the passivation film PAS. The passivation film PAS canbe formed over almost entire upper surface of the glass substrate GS.

The passivation film PAS has a function of preventing moisture fromentering the organic EL element (in particular, organic layer OEL) froma side of the glass substrate GS. Therefore, the passivation film PASfunctions as a protection film on a lower side of the organic ELelement. On the other hand, a protection film PF functions as aprotection film on an upper side of the organic EL element, and has afunction of preventing moisture from entering the organic EL element (inparticular, organic layer OEL) from an upper side.

The organic EL element is formed over the upper surface of the glasssubstrate GS with the passivation film PAS interposed therebetween. Theorganic EL element is made up of the lower electrode layer ELB, theorganic layer OEL, and the upper electrode layer ELA. Namely, over thepassivation film PAS over the glass substrate GS, the lower electrodelayer ELB, the organic layer OEL, and the upper electrode layer ELA arestacked in this order from below, and the organic EL element is composedof the lower electrode layer ELB, the organic layer OEL, and the upperelectrode layer ELA.

The lower electrode layer ELB constitutes one of an anode and a cathode,and the upper electrode layer ELA constitutes the other of the anode andthe cathode. Namely, when the lower electrode layer ELB is an anode(anode layer), the upper electrode layer ELA is a cathode (cathodelayer), and when the lower electrode layer ELB is a cathode (cathodelayer), the upper electrode layer ELA is an anode (anode layer). Each ofthe lower electrode layer ELB and the upper electrode layer ELA is madeof a conductive film.

One of the lower electrode layer ELB and the upper electrode layer ELAis desirably composed of a metal film such as an aluminum film (Al film)so as to be able to function as a reflection electrode. Also, the otherof the lower electrode layer ELB and the upper electrode layer ELA isdesirably composed of a transparent conductor film made of ITO (indiumtin oxide) or the like so as to be able to function as a transparentelectrode. When the so-called bottom emission type in which light isemitted from a lower surface side of the glass substrate GS is adopted,the lower electrode layer ELB can be formed as the transparentelectrode. On the other hand, when the so-called top emission type inwhich light is emitted from an upper surface side of the glass substrateGS is adopted, the upper electrode layer ELA can be formed as thetransparent electrode. In addition, when the bottom emission type isadopted, a transparent substrate having translucency to visible lightcan be used as the glass substrate GS.

Since the lower electrode layer ELB is formed over the passivation filmPAS over the glass substrate GS, the organic layer OEL is formed overthe lower electrode layer ELB, and the upper electrode layer ELA isformed over the organic layer OEL, the organic layer OEL is interposedbetween the lower electrode layer ELB and the upper electrode layer ELA.

The organic layer OEL includes at least an organic light emission layer.The organic layer OEL can further include any of a hole transport layer,a hole implantation layer, an electron transport layer, and an electronimplantation layer as needed in addition to the organic light emissionlayer. Therefore, for example, the organic layer OEL is configured tohave a single layer structure of an organic light emission layer, astacked layer structure including a hole transport layer, an organiclight emission layer, and an electron transport layer, or a stackedlayer structure including a hole implantation layer, a hole transportlayer, an organic light emission layer, an electron transport layer, andan electron implantation layer.

For example, as shown in FIG. 2, the lower electrode layers ELB form astripe-shaped pattern extending in the x direction. Namely, a pluralityof the lower electrode layers ELB are arranged in the y direction atpredetermined intervals while extending in the x direction. On the otherhand, the upper electrode layers ELA form a stripe-shaped patternextending in the y direction. Namely, a plurality of the upper electrodelayers ELA are arranged in the x direction at predetermined intervalswhile extending in the y direction. In other words, the lower electrodelayers ELB are made up of a stripe-shaped electrode group extending inthe x direction, and the upper electrode layers ELA are made up of astripe-shaped electrode group extending in the y direction. Here, the xdirection and the y direction are directions intersecting with eachother, more specifically, directions orthogonal to each other. Also, thex direction and the y direction are directions substantially parallel tothe upper surface of the glass substrate GS.

Since the extending direction of the lower electrode layer ELB is the xdirection and the extending direction of the upper electrode layer ELAis the y direction, the lower electrode layer ELB and the upperelectrode layer ELA intersect with each other in plan view. Note that“in plan view” means the case of being seen on a plane substantiallyparallel to the upper surface of the glass substrate GS.

At each intersection portion between the lower electrode layer ELB andthe upper electrode layer ELA, the organic layer OEL is sandwiched bythe lower electrode layer ELB and the upper electrode layer ELA disposedone above the other. Accordingly, at each intersection portion betweenthe lower electrode layer ELB and the upper electrode layer ELA, theorganic EL element made up of the lower electrode ELB, the upperelectrode ELA, and the organic layer OEL is formed, and the organic ELelement forms the pixel. By applying a predetermined voltage between thelower electrode ELB and the upper electrode ELA, the organic lightemission layer in the organic layer OEL sandwiched between the lowerelectrode ELB and the upper electrode ELA emits light.

Note that the organic layer OEL may be formed over the entire displayunit DU, and may be formed to have the same pattern as the lowerelectrode layer ELB. Similarly, the organic layer OEL may be formed tohave the same pattern as the upper electrode layer ELA. In any case, theorganic layer OEL is present at each intersection portion between thelower electrode layer ELB and the upper electrode layer ELA.

As described above, in the display unit DU, the organic EL elementsconstituting the pixels are arranged in an array over the glasssubstrate GS in plan view.

Note that the case in which the lower electrode layers ELB and the upperelectrode layers ELA are configured of stripe-shaped patterns isdescribed here. Therefore, in the plurality of organic EL elements(pixels) arranged in an array, the organic EL elements arranged in the xdirection have the common lower electrode layer ELB. Meanwhile, theorganic EL elements arranged in the y direction have the common upperelectrode layer ELA. However, the structure of the organic EL elementsarranged in an array is not limited to this and can be changed invarious ways.

For example, the case in which the plurality of organic EL elementsarranged in an array are not connected by any of the upper electrodelayer ELA and the lower electrode layer ELB and are arrangedindependently is also possible. In this case, each of the organic ELelements is formed of an isolated pattern having a stacked layerstructure of the lower electrode layer, the organic layer, and the upperelectrode layer, and a plurality of the isolated organic EL elements arearranged in an array. In this case, in each pixel, an active elementsuch as a TFT (Thin Film Transistor) is provided in addition to theorganic EL element, and the pixels can be connected through wirings.

The protection film PF is formed over the upper surface of the glasssubstrate GS (passivation film PAS) so as to cover the organic ELelement, that is, the lower electrode layer ELB, the organic layer OEL,and the upper electrode layer ELA. When the organic EL elements arearranged in an array in the display unit DU, the protection film PF isformed so as to cover the organic EL elements arranged in an array.Therefore, the protection film PF is desirably formed over the entiredisplay unit DU. Also, the protection film PF is desirably formed overthe almost entire upper surface of the glass substrate GS. By coveringthe organic EL element with the protection film PF, it is possible toprevent the entrance of moisture into the organic EL element (inparticular, entrance of moisture into the organic layer OEL) by theprotection film PF.

A resin film PIF is formed over the protection film PF. As a material ofthe resin film PIF, for example, PET (polyethylene terephthalate) can beused. The formation of the resin film PIF may be omitted. However, thecase in which the resin film PIF is formed is more desirable than thecase in which the resin film PIF is not formed. Since the resin film PIFis soft, the display unit DU can be easily handled when the resin filmPIF is provided. In the manner described above, the display unit DU ofthe mobile phone MP is configured.

<Manufacturing Method of Display Unit>

Next, a manufacturing method of the display unit DU will be describedwith reference to a drawing. FIG. 4 is a flowchart showing amanufacturing process of the display unit DU. First, for example, aglass substrate having translucency to visible light is prepared (S101).Then, the passivation film is formed over the upper surface of the glasssubstrate (S102). The passivation film can be formed by using, forexample, the sputtering method, the CVD (Chemical Vapor Deposition)method, and the ALD (Atomic Layer Deposition) method. The passivationfilm is made of an insulating material, for example, a silicon oxidefilm. In particular, a silicon oxide film formed by the CVD method canbe used as the passivation film.

Next, the organic EL element made up of the lower electrode layer, theorganic layer over the lower electrode layer, and the upper electrodelayer over the organic layer is formed over the passivation film.Namely, the lower electrode layer, the organic layer, and the upperelectrode layer are formed in this order from below over the passivationfilm (S103 to S105). For example, this process can be performed asfollows.

Namely, the lower electrode layer is formed over the passivation film(S103). For example, the lower electrode layer can be formed by forminga conductive film over the passivation film and patterning theconductive film by the photolithography technology and the etchingtechnology. Thereafter, the organic layer is formed over the lowerelectrode layer (S104). For example, the organic layer can be formed bythe evaporation method (vacuum evaporation method) using a mask. Then,the upper electrode layer is formed over the organic layer (S105). Forexample, the upper electrode layer can be formed by the evaporationmethod using a mask.

Subsequently, after the organic EL element made up of the lowerelectrode layer, the organic layer, and the upper electrode layer isformed, the protection film is formed over the upper electrode (S106).The protection film is formed so as to cover the organic EL element.When a plurality of organic EL elements are arranged in an array, theplurality of organic EL elements are covered with the protection film.The protection film is made of, for example, an aluminum oxide film.

Thereafter, the resin film is formed over the protection film (S107).The resin film is made of, for example, PET and can be formed by thespin coating method. In the manner described above, the display unit DUcan be manufactured.

<Connection Configuration between Display Unit and Circuit Unit>

In order to display an image on the display unit, it is necessary todrive and control the plurality of pixels (organic EL elements)constituting the display unit, and the function of driving andcontrolling the organic EL elements is implemented by the circuit unit.Therefore, in order to display an image on the display unit, it isnecessary to electrically connect the display unit to the circuit unit.

FIG. 5 is a diagram schematically showing a configuration example ofelectrically connecting the display unit DU and a circuit unit CRU. Asshown in FIG. 5, an electrode EL1 electrically connected to the pixels(organic EL elements) constituting the display unit DU is formed in aframe region surrounding the display unit DU, and the electrode EL1formed in the frame region is electrically connected to the pixels(organic EL elements) constituting the display unit DU. Then, theelectrode EL1 is connected to an electrode EL2 formed in a connectiontape electrode TE. Further, an electrode EL3 electrically connected tothe electrode EL2 is also formed in the connection tape electrode TEtogether with the electrode EL2, and the electrode EL3 is electricallyconnected to the circuit unit CRU. Therefore, the display unit DU iselectrically connected to the circuit unit CRU through the path of theelectrode EL1 formed in the frame region, the electrode EL2 formed inthe connection tape electrode TE, and the electrode EL3 formed in theconnection tape electrode TE.

Here, by disposing the electrode EL2 formed in the connection tapeelectrode TE so as to overlap the electrode EL1 formed in the frameregion surrounding the display unit DU, the electrode EL1 formed in theframe region is electrically connected to the electrode EL2 constitutingthe connection tape electrode TE. Accordingly, in order to ensure theelectrical connection between the electrode EL1 and the electrode EL2,it is necessary to form the protection film so as not to cover theelectrode EL1. This is because when the protection film made of aninsulating film is formed so as to cover the electrode EL1, theelectrode EL1 cannot be electrically connected to the electrode EL2 ofthe connection tape electrode TE.

Therefore, it is necessary to form the protection film so as to coverthe pixels (organic EL elements) formed in the display unit DU in orderto protect the organic EL elements from the entrance of moisture, andfurther it is necessary to prevent the protection film from being formedin the frame region in which the electrode EL1 is formed in order toensure the conduction between the electrode EL1 and the electrode EL2 ofthe connection tape electrode TE.

<Necessity of Mask in Formation of Protection Film>

As described above, it is necessary to form the protection film so as tocover the pixels (organic EL elements) formed in the display unit DU,and it is also necessary to prevent the protection film from beingformed in the frame region in which the electrode EL1 is formed. Here,since one glass substrate GS includes a plurality of regions in whichthe display unit DU is formed as shown in FIG. 6, if the protection filmis formed without using the mask over the entire main surface of theglass substrate GS in which the organic EL elements have been formed,the protection film is formed not only over the display unit DU but alsoover the frame region surrounding the display unit DU. This means thatthe protection film is formed so as to cover the electrode EL1 formed inthe frame region, so that the conduction between the electrode EL1 andthe electrode EL2 of the connection tape electrode TE cannot be ensured.Therefore, the mask is necessary when forming the protection film.Namely, as shown in FIG. 6, the protection film is formed in the statewhere a mask MSK having an opening region OPR corresponding to thedisplay unit DU and a cover region CVR corresponding to the frame regionis overlapped with the glass substrate GS. In this case, the protectionfilm is formed in the region (region in which the display unit DU isformed) of the glass substrate GS exposed from the opening region OPRformed in the mask MSK, whereas the protection film is not formed in theregion (region to be the frame region) of the glass substrate GS coveredwith the cover region CVR formed in the mask MSK. As described above,when forming the protection film, the mask MSK having the opening regionOPR corresponding to the display unit DU and the cover region CVRcorresponding to the frame region is used. As a result, it is possibleto form the protection film so as to cover the pixels (organic ELelements) formed in the display unit DU, and it is also possible toprevent the protection film from being formed in the frame region inwhich the electrode EL1 is formed.

<Reason for Using Atomic Layer Deposition Method (ALD Method) forFormation of Protection Film>

Next, the protection film that protects the organic EL element from theentrance of moisture is formed by, for example, the atomic layerdeposition method (ALD method), and the reason therefor will bedescribed below.

The atomic layer deposition method is a film-forming method in which afilm is formed over a substrate in a unit of atomic layer by alternatelysupplying source gas and reaction gas to the substrate. The atomic layerdeposition method forms a film in a unit of atomic layer, and thus hasan advantage of excellent step coverage and film thicknesscontrollability. Also, according to the atomic layer deposition methodhaving the advantage of excellent step coverage, in particular, aprotection film capable of exerting the function of sufficientlyprotecting the organic EL element from the entrance of moisture can beformed while reducing the film thickness thereof. Therefore, the atomiclayer deposition method is used to form the protection film thatprotects the organic EL element from the entrance of moisture.

For example, the case where the protection film PF is formed over theglass substrate GS having a foreign particle PCL adhered thereto isconsidered. Here, as a forming method of the protection film PF, the CVDmethod may be used. However, as the forming tendency of the protectionfilm by the CVD method, the vertical directionality tends to be strong.Therefore, if the protection film PF is formed by the CVD method overthe glass substrate GS to which the foreign particle PCL is adhered asshown in FIG. 7(a), the protection film PF is not formed so as to coverthe foreign particle PCL due to the tendency of strong verticaldirectionality. As a result, a dead space in which no protection film PFis formed is formed around the foreign particle PCL, and the entrance ofmoisture is likely to occur through the dead space. Namely, even whenthe protection film PF is intended to be formed by the CVD method so asto cover the glass substrate GS to which the foreign particle PCL isadhered, the dead space in which no protection film PF is formed isformed at the step difference portion between the foreign particle PCLand the glass substrate GS due to the tendency of strong verticaldirectionality, resulting in the entrance of moisture into the organicEL element through the dead space. Therefore, when the protection filmPF is formed by the CVD method, for example, the protection film PF isformed so as to completely cover the foreign particle PCL adhered to theglass substrate GS by increasing the thickness of the protection filmformed by the CVD method as shown in FIG. 7(b). In other words, when theprotection film PF is formed by the CVD method having the strongvertical directionality, the occurrence of the dead space in which noprotection film PF is formed at the step difference portion between theforeign particle PCL and the glass substrate GS is suppressed byincreasing the thickness of the protection film PF. Namely, since it isdifficult to completely suppress the adhesion of the foreign particlePCL to the glass substrate GS, when the CVD method is used to form theprotection film PF, the thickness of the protection film PF must beincreased in order to effectively prevent the entrance of moisture intothe organic EL element by the protection film PF in consideration of theforeign particle PCL adhered to the glass substrate GS.

On the other hand, the case in which the plasma atomic layer depositionmethod is used as the forming method of the protection film PF isconsidered. For example, in the plasma atomic layer depositionapparatus, a film is formed in a unit of atomic layer over the substrateby alternately supplying source gas and reaction gas between a lowerelectrode that holds the substrate and an upper electrode disposed toface the lower electrode and performing plasma discharge when supplyingthe source gas. At this time, in the plasma atomic layer depositionapparatus, the film is formed in a unit of atomic layer, and thus, thefilm excellent in step coverage can be formed. In particular, in theplasma atomic layer deposition apparatus, in order to achieve preferablestep coverage, a material that easily diffuses is used as the sourcegas, and each gas (source gas, purge gas, and reaction gas) isalternately supplied while securing the time for sufficiently diffusingeach gas in the film-forming container. Therefore, in the plasma atomiclayer deposition apparatus, the source gas and the reaction gas react toform the film even in the minute gap. Namely, since the plasma atomiclayer deposition apparatus has the characteristics of (1) the film isformed in a unit of atomic layer, (2) the source gas and the reactiongas spread in every corner of the minute gap, and (3) the source gas andthe reaction gas easily react even in the place where the plasmadischarge is not generated, the film is formed even in the minute gap.

As a result, in the plasma atomic layer deposition method, the advantageof excellent step coverage can be obtained, and thus, the protectionfilm PF can be formed so as to cover the glass substrate GS to which theforeign particle PCL is adhered even if the thickness of the protectionfilm PF is reduced as shown in FIG. 8. Namely, since the plasma atomiclayer deposition method is excellent in step coverage, the occurrence ofthe dead space in which no protection film PF is formed at the stepdifference portion between the foreign particle PCL and the glasssubstrate GS can be prevented, and thus, the entrance of moisture intothe organic EL element can be effectively suppressed while reducing thethickness of the protection film PF. In other words, when the protectionfilm PF is formed by the plasma atomic layer deposition method, theprotection film PF that can effectively suppress the entrance ofmoisture into the organic EL element can be formed without increasingthe film thickness thereof.

As described above, according to the plasma atomic layer depositionmethod having the advantage of excellent step coverage, even when theforeign particle PCL is adhered to the glass substrate GS, theprotection film PF excellent in the prevention of the entrance ofmoisture can be formed without increasing the film thickness thereof.Accordingly, it is desirable that the protection film PF thateffectively protects the organic EL element from the entrance ofmoisture is formed by using the plasma atomic layer deposition method.

As described above, since the thickness of the protection film PF can bereduced when the protection film PF is formed by the plasma atomic layerdeposition method, it is also effective to apply the protection film PFformed by the plasma atomic layer deposition method to the configurationin which the display unit DU is formed over the flexible substrate orthe like.

FIG. 9 is a diagram schematically showing a state in which a flexiblesubstrate 1S is used as the substrate of the display unit DU and thisflexible substrate 1S is bent. FIG. 9 shows a bending state of thedisplay unit DU in which the passivation film PAS is formed over theflexible substrate 1S, an organic EL layer OLDL is formed over thepassivation film PAS, the protection film PF is formed over the organicEL layer OLDL, and the resin film PIF is formed over the protection filmPF. It can be seen that the display unit DU can be bent by forming thedisplay unit DU over the flexible substrate 1S as described above. Whenthe flexible substrate 1S is used as the substrate, there is a risk thatcracks may occur in the protection film PF made of an inorganicinsulating film when it is bent. Therefore, the protection film PF madeof an inorganic insulating film is desirably made as thin as possible.

In this respect, when the flexible substrate 1S is used as thesubstrate, the thickness of the protection film PF can be reduced byadopting the protection film PF formed by using the plasma atomic layerdeposition method. As a result, the protection film PF formed by theplasma atomic layer deposition method is useful in that it is possibleto efficiently obtain the effect of preventing the entrance of moistureby the protection film PF while suppressing the occurrence of cracks inthe protection film PF made of an inorganic insulating film.

<Film-Forming Method of Protection Film by Plasma Atomic LayerDeposition Method>

As described above, in order to effectively protect the organic ELelement from the entrance of moisture while reducing the thickness ofthe protection film PF, it is useful to form the protection film by theplasma atomic layer deposition method. Thus, the forming method of theprotection film by the plasma atomic layer deposition method will bedescribed below. FIG. 10 is a flowchart for describing the formingmethod of the protection film by the plasma atomic layer depositionmethod.

First, the glass substrate is prepared, and the glass substrate isloaded over the lower electrode (stage) of the plasma atomic layerdeposition apparatus. Subsequently, source gas is introduced into thefilm-forming container (process chamber) from a gas supply unit of theplasma atomic layer deposition apparatus (S201). At this time, thesource gas is supplied into the film-forming container for, for example,0.1 second. Consequently, the source gas is supplied into thefilm-forming container, and the source gas is adsorbed to the glasssubstrate and an adsorption layer is formed.

Subsequently, the supply of the source gas is stopped, and purge gas isintroduced into the film-forming container (process chamber) from thegas supply unit (S202). Consequently, the purge gas is supplied into thefilm-forming container, and the source gas is exhausted to the outsideof the film-forming container from an exhaust unit. The purge gas issupplied into the film-forming container for, for example, 0.1 second.Then, the exhaust unit exhausts the source gas and the purge gas in thefilm-forming container for, for example, 2 seconds. Consequently, thepurge gas is supplied into the film-forming container and the source gaswhich is not adsorbed to the glass substrate is purged from thefilm-forming container.

Next, reaction gas is supplied from the gas supply unit (S203).Consequently, the reaction gas is supplied into the film-formingcontainer. The reaction gas is supplied into the film-forming containerfor, for example, 1 second. In the step of supplying the reaction gas,plasma discharge is generated by applying a discharge voltage betweenthe upper electrode and the lower electrode (S204). As a result,radicals (active species) are generated in the reaction gas. In themanner described above, the reaction gas is supplied into thefilm-forming container and the adsorption layer adsorbed to the glasssubstrate chemically reacts with the reaction gas, so that theprotection film made of an atomic layer is formed.

Subsequently, the supply of the reaction gas is stopped, and purge gasis supplied from the gas supply unit (S205). Consequently, the purge gasis supplied into the film-forming container, and the reaction gas isexhausted to the outside of the film-forming container from the exhaustunit. The purge gas is supplied into the film-forming container for, forexample, 0.1 second. Then, the exhaust unit exhausts the reaction gasand the purge gas in the film-forming container for, for example, 2seconds. Consequently, the purge gas is supplied into the film-formingcontainer, and the excessive reaction gas which is not used for thereaction is purged from the film-forming container.

In the manner described above, the protection film made of one atomiclayer is formed over the glass substrate. Thereafter, by repeating theabove-described steps (S201 to S205) a predetermined number of times(S206), the protection film made of a plurality of atomic layers isformed. Consequently, the film-forming process is completed (S207). Inthe manner described above, the protection film PF can be formed by theplasma atomic layer deposition method.

<Study for Improvement>

As described above, the protection film that protects the organic ELelement from the entrance of moisture can be formed by the plasma atomiclayer deposition method using the mask having the opening regioncorresponding to the display unit and the cover region corresponding tothe frame region.

At this time, the study by the inventors of the present invention hasnewly revealed that there is a room for improvement in the process offorming the protection film by the plasma atomic layer deposition methodusing the mask having the opening region corresponding to the displayunit and the cover region corresponding to the frame region. Thus, a“related technology 1” having the room for improvement will be describedbelow with reference to the drawings.

<<Assumptions>>

First, as described in the paragraph of “<Necessity of Mask in Formationof Protection Film>”, the mask MSK is necessary when forming theprotection film, and the mask MSK has substantially the same size as theglass substrate GS as shown in FIG. 6. This is because the protectionfilm needs to be formed at a time over all of the regions of the glasssubstrate GS corresponding to the plurality of display units DU, and allof the regions to be the frame regions (regions other than the pluralityof display units DU) need to be covered so as not to form the protectionfilm in all of the frame regions when forming the protection film.Incidentally, in recent years, from the viewpoint of improving themanufacturing efficiency, the size of the glass substrate GS has beenincreasing in order to increase the number of display units DU acquiredfrom one glass substrate GS. This means that the size of the mask MSKhaving substantially the same size as the glass substrate GS is alsoincreased. Also, the increase in size of the mask MSK leads to thesituation in which it is difficult to ensure the flatness of the maskMSK. This is because the weight of the mask MSK itself increases due tothe increase in size of the mask MSK and the deflection is thus likelyto occur in the mask MSK, making it difficult to ensure the flatness ofthe mask MSK. Then, due to the decrease in the flatness of the mask MSK,the room for improvement becomes more apparent. Hereinafter, the roomfor improvement present in the “related technology 1” taken as anexample will be described below with reference to the drawings.

<<Description of Related Technology 1>>

FIG. 11 is a schematic diagram showing a state in which source gas isintroduced into a process chamber of a plasma atomic layer depositionapparatus in the related technology 1. In FIG. 11, a substrate loadingunit SLU is provided in the process chamber in the related technology 1.This substrate loading unit SLU includes a stage ST and a susceptor SPdisposed over the stage ST, and the glass substrate GS having theorganic EL element formed therein is loaded over the susceptor SP.

Also, as shown in FIG. 11, the mask MSK is disposed over the glasssubstrate GS. At this time, the planar size of the mask MSK is increasedso as to correspond to the large glass substrate GS, and the flatness ofthe mask MSK is decreased. As a result, as shown in FIG. 11, a minutegap is present between the glass substrate GS and the mask MSK in therelated technology 1.

Further, in the process chamber, the upper electrode UE is disposed atthe position facing the mask MSK, and the space sandwiched between themask MSK and the upper electrode UE serves as the film-forming space.Also, the source gas SG is introduced into the film-forming space fromthe gas supply unit (not shown). The source gas SG is made of, forexample, trimethyl aluminum (TMA). Further, the source gas SG enters theminute gap between the glass substrate GS and the mask MSK. Note that,at the stage shown in FIG. 11, no high frequency voltage is applied tothe upper electrode UE, and no plasma is generated in the film-formingspace.

Next, FIG. 12 is a schematic diagram showing a state in which purge gasis introduced into the process chamber of the plasma atomic layerdeposition apparatus in the related technology 1. At this time, purgegas made of, for example, nitrogen gas is supplied into the processchamber from the gas supply unit (not shown). Consequently, the sourcegas SG remaining in the process space is exhausted from the processspace. Even at this stage, the minute gap is still present between themask MSK and the glass substrate GS. Note that, even at the stage shownin FIG. 12, no high frequency voltage is applied to the upper electrodeUE, and no plasma is generated in the film-forming space.

Subsequently, FIG. 13 is a schematic diagram showing a state in whichreaction gas is introduced into the process chamber of the plasma atomiclayer deposition apparatus in the related technology 1. At this time,reaction gas AG made of, for example, oxygen gas is supplied into theprocess chamber from the gas supply unit (not shown). Even at thisstage, the minute gap is still present between the mask MSK and theglass substrate GS, and the reaction gas AG is supplied also to theminute gap in the related technology 1. Note that, even at the stageshown in FIG. 13, no high frequency voltage is applied to the upperelectrode UE, and no plasma is generated in the film-forming space.

Next, FIG. 14 is a schematic diagram showing a state in which plasma isgenerated in the process chamber of the plasma atomic layer depositionapparatus in the related technology 1. At this time, the reaction gas AGmade of, for example, oxygen gas is supplied into the process chamberfrom the gas supply unit (not shown). Even at this stage, the minute gapis still present between the mask MSK and the glass substrate GS, andthe reaction gas AG is supplied also to the minute gap in the relatedtechnology 1. Here, at the stage shown in FIG. 14, the high frequencyvoltage is applied to the upper electrode UE from a high frequency powersource RFS. Consequently, plasma PLS containing radicals (activespecies) and charged particles is generated in the film-forming space.Then, by this plasma PLS, the adsorption layer formed over the glasssubstrate GS by introducing the source gas SG reacts with the reactiongas AG converted into plasma, and the protection film made of, forexample, an aluminum oxide film is formed so as to cover the organic ELelement formed in the glass substrate GS.

Subsequently, FIG. 15 is a schematic diagram showing a state in whichpurge gas is introduced into the process chamber of the plasma atomiclayer deposition apparatus in the related technology 1. At this time,purge gas made of, for example, nitrogen gas is supplied into theprocess chamber from the gas supply unit (not shown). Consequently, thereaction gas AG remaining in the process space is exhausted from theprocess space. Even at this stage, the minute gap is still presentbetween the mask MSK and the glass substrate GS. Note that, at the stageshown in FIG. 15, the application of the high frequency voltage to theupper electrode UE is stopped. As a result, the plasma PLS generated inthe film-forming space disappears.

In the manner described above, in the related technology 1, theprotection film made of, for example, an aluminum oxide film can beformed so as to cover the organic EL element formed in the glasssubstrate GS by the plasma atomic layer deposition method using the maskMSK.

<<Description of Room for Improvement>>

Subsequently, the room for improvement present in the related technology1 will be described. In the related technology 1, the mask having theopening region corresponding to the display unit and the cover regioncorresponding to the frame region is used, and it is thus conceived thatthe protection film is not formed in the frame region of the glasssubstrate. However, in the related technology 1, since (1) the minutegap is present between the mask and the glass substrate and (2) theforming method of the protection film is the plasma atomic layerdeposition method, the protection film is formed also in a part of theframe region of the glass substrate. For example, FIG. 16 is a diagramschematically showing a state in which the protection film is formed soas to enter the minute gap between the glass substrate GS and the maskMSK. In this case, the electrode electrically connected to the displayunit is formed in the frame region present below the mask MSK, and whenthe protection film made of an insulating material is formed over theelectrode, the conduction between the display unit and the circuit unitthrough the electrode cannot be ensured.

Namely, since it becomes difficult to ensure the flatness of the maskwith the increase in size of the mask, the minute gap is present betweenthe mask and the glass substrate. Further, in the plasma atomic layerdeposition method used to form the protection film, in order to achievepreferable step coverage, a material that easily diffuses is used as thesource gas, and each gas (source gas, purge gas, and reaction gas) isalternately supplied while securing the time for sufficiently diffusingeach gas in the film-forming container. Therefore, for example, thesource gas and the reaction gas spread not only to the substrate butalso in every corner of the film-forming container. Also, in the plasmaatomic layer deposition apparatus, the film is formed by generatingactive species (radicals) by the plasma discharge in the reaction gasand reacting the active species with the source gas adsorbed to thesubstrate, and in addition, the source gas and the reaction gas tend toreact with each other even in a state where the active species(radicals) are not generated by plasma discharge. Therefore, in theplasma atomic layer deposition apparatus, the source gas and thereaction gas react with each other to form the film even in the minutegap in which the plasma discharge is not generated. In other words,since the atomic layer deposition apparatus has the characteristics of(1) the film is formed in a unit of atomic layer, (2) the source gas andthe reaction gas spread in every corner of the film-forming container,and (3) the source gas and the reaction gas easily react even in theplace where the plasma discharge is not generated, the film is formedeven in the minute gap formed between the mask and the glass substrate.

FIG. 17 is a graph showing a relationship between a distance of entrancefrom a mask edge toward the mask and a thickness of the formedprotection film. In FIG. 17, the horizontal axis represents the distance(mm) of entrance from the mask edge toward the mask, and the verticalaxis represents the thickness (nm) of the formed protection film. As canbe seen from FIG. 17, the protection film is formed even at the positionentered from the mask edge toward the mask. Namely, according to themeasurement results shown in FIG. 17, it can be seen that the protectionfilm is formed also in a part of the frame region of the glass substratethat is supposed to be covered with the mask in the relatedtechnology 1. Incidentally, in the mobile phone (smartphone), it isdesired that the size of the display unit is increased and the size ofthe frame region is reduced as much as possible. This is because it isdesired that the overall size of the mobile phone is reduced whileensuring the size of the display unit in the mobile phone (smartphone).In this respect, when the size of the frame region is reduced in therelated technology 1, there is a high possibility that the protectionfilm is formed so as to cover the electrode formed in the frame regiondue to the entrance of the protection film. In this case, there is aconcern that the conduction between the display unit and the circuitunit through the electrode cannot be ensured. On the other hand, whenthe frame region is configured to have a larger size to form theelectrode in an inner region where the entrance of the protection filmdoes not occur, the size of the frame region is increased, so that theoverall size of the mobile phone is increased even though the size ofthe display unit is not increased. Accordingly, it can be seen thatthere is a room for improvement from the viewpoint of ensuring theelectrical connection reliability between the display unit and thecircuit unit through the electrode formed in the frame region whilereducing the size of the frame region in the related technology 1.

Here, since the main cause of the entrance of the protection film intothe frame region is the formation of the minute gap between the glasssubstrate and the mask, the elimination of the minute gap is considered.In particular, since the minute gap is caused by the decrease in theflatness of the mask, it is conceivable to eliminate the gap by theselection of the mask material constituting the mask. For example, whenthe mask material is made of metal, the distance of entrance of theprotection film is about 3 mm. On the other hand, when the mask materialis made of ceramic, the distance of entrance of the protection film isabout 1 mm. Accordingly, it seems that the entrance of the protectionfilm into the frame region can be suppressed by changing the maskmaterial from metal to ceramic. However, even when the mask material ischanged to ceramic, the decrease in the flatness of the mask cannot becompletely solved, and in particular, there is a concern that theentrance of the protection film into the frame region expands due to theincrease in size of the mask even when the mask is made of ceramic. Asdescribed above, changing the mask material in order to suppress theentrance of the protection film into the frame region is not anessential measure, and a further fundamental measure is needed.

Thus, in a related technology 2, a contrivance of making the mask from amagnetic substance and forcibly attracting the mask to the glasssubstrate by the magnetic force of the magnet provided outside isapplied for suppressing the formation of the minute gap between theglass substrate and the mask to be the main cause of the entrance of theprotection film into the frame region. Hereinafter, the relatedtechnology 2 to which the contrivance is applied will be described.

<Description of Related Technology 2>

FIG. 18 is a schematic diagram showing a state in which source gas isintroduced into a process chamber of a plasma atomic layer depositionapparatus in the related technology 2. In FIG. 18, a substrate loadingunit SLU is provided in the process chamber in the related technology 2.This substrate loading unit SLU includes a stage ST and a susceptor SPdisposed over the stage ST, and a permanent magnet PM functioning as amagnetic field generating unit MGU is embedded in the susceptor SP.Further, the glass substrate GS having the organic EL element formedtherein is loaded over the susceptor SP. Also, as shown in FIG. 18, themask MSK made of a magnetic substance is disposed over the glasssubstrate GS. Therefore, in the related technology 2, since the mask MSKmade of a magnetic substance is attracted to the permanent magnet PM,the minute gap is not present between the mask MSK and the glasssubstrate GS.

Further, in the process chamber, the upper electrode UE is disposed atthe position facing the mask MSK, and the space sandwiched between themask MSK and the upper electrode UE serves as the film-forming space.Also, the source gas SG is introduced into the film-forming space fromthe gas supply unit (not shown). The source gas SG is made of, forexample, trimethyl aluminum (TMA). At this time, since the minute gap isnot present between the mask MSK and the glass substrate GS in therelated technology 2, the source gas SG does not enter between the glasssubstrate GS and the mask MSK. Note that, at the stage shown in FIG. 18,no high frequency voltage is applied to the upper electrode UE, and noplasma is generated in the film-forming space.

Next, FIG. 19 is a schematic diagram showing a state in which purge gasis introduced into the process chamber of the plasma atomic layerdeposition apparatus in the related technology 2. At this time, purgegas made of, for example, nitrogen gas is supplied into the processchamber from the gas supply unit (not shown). Consequently, the sourcegas SG remaining in the process space is exhausted from the processspace. Even at this stage, since the mask MSK made of a magneticsubstance is still attracted to the permanent magnet PM, the minute gapis not present between the mask MSK and the glass substrate GS. Notethat, even at the stage shown in FIG. 19, no high frequency voltage isapplied to the upper electrode UE, and no plasma is generated in thefilm-forming space.

Subsequently, FIG. 20 is a schematic diagram showing a state in whichreaction gas is introduced into the process chamber of the plasma atomiclayer deposition apparatus in the related technology 2. At this time,reaction gas AG made of, for example, oxygen gas is supplied into theprocess chamber from the gas supply unit (not shown). Even at thisstage, since the mask MSK made of a magnetic substance is attracted tothe permanent magnet PM, the minute gap is not present between the maskMSK and the glass substrate GS. Accordingly, the reaction gas AG doesnot enter between the glass substrate GS and the mask MSK. Note that,even at the stage shown in FIG. 20, no high frequency voltage is appliedto the upper electrode UE, and no plasma is generated in thefilm-forming space.

Next, FIG. 21 is a schematic diagram showing a state in which plasma isgenerated in the process chamber of the plasma atomic layer depositionapparatus in the related technology 2. At this time, the reaction gas AGmade of, for example, oxygen gas is supplied into the process chamberfrom the gas supply unit (not shown). Even at this stage, since the maskMSK made of a magnetic substance is still attracted to the permanentmagnet PM, the minute gap is not present between the mask MSK and theglass substrate GS. Accordingly, the reaction gas AG does not enterbetween the glass substrate GS and the mask MSK.

Here, at the stage shown in FIG. 21, the high frequency voltage isapplied to the upper electrode UE from a high frequency power sourceRFS. Consequently, plasma PLS containing radicals (active species) andcharged particles is generated in the film-forming space. Then, by thisplasma PLS, the adsorption layer formed over the glass substrate GS byintroducing the source gas SG reacts with the reaction gas AG convertedinto plasma, and the protection film made of, for example, an aluminumoxide film is formed so as to cover the organic EL element formed in theglass substrate GS.

Subsequently, FIG. 22 is a schematic diagram showing a state in whichpurge gas is introduced into the process chamber of the plasma atomiclayer deposition apparatus in the related technology 2. At this time,purge gas made of, for example, nitrogen gas is supplied into theprocess chamber from the gas supply unit (not shown). Consequently, thereaction gas AG remaining in the process space is exhausted from theprocess space. Even at this stage, since the mask MSK made of a magneticsubstance is still attracted to the permanent magnet PM, the minute gapis not present between the mask MSK and the glass substrate GS. Notethat, at the stage shown in FIG. 22, the application of the highfrequency voltage to the upper electrode UE is stopped. As a result, theplasma PLS generated in the film-forming space disappears.

In the manner described above, in the related technology 2, theprotection film made of, for example, an aluminum oxide film can beformed so as to cover the organic EL element formed in the glasssubstrate GS by the plasma atomic layer deposition method using the maskMSK.

<Room for Improvement Specific to Related Technology 2>

In the related technology 2 described above, as shown in FIGS. 18 to 22,since the mask MSK made of a magnetic substance is attracted to thepermanent magnet PM during the film-forming operation, the minute gap isnot present between the mask MSK and the glass substrate GS.Accordingly, in the related technology 2, the entrance of the protectionfilm into the frame region covered with the mask MSK can be prevented.In other words, since the adhesion between the mask MSK made of amagnetic substance and the glass substrate GS can be improved by themagnetic force based on the magnetic field generated from the permanentmagnet PM in the related technology 2, the formation of the protectionfilm in the frame region can be suppressed.

However, in the related technology 2, for example, as shown in FIG. 21,the magnetic field from the permanent magnet PM embedded in thesusceptor SP leaks to the film-forming space even in the state in whichthe plasma PLS is generated. Accordingly, the plasma PLS generated inthe film-forming space is affected by the magnetic field. Also, sincethe plasma PLS contains the charged particles, the Lorentz force acts onthe charged particles, so that the film thickness distribution of theprotection film formed over the glass substrate GS is disturbed.

As described above, in the related technology 2, by making the mask MSKfrom a magnetic substance and embedding the permanent magnet PM in thesubstrate loading unit SLU, the mask MSK is forcibly attracted to theglass substrate GS by the magnetic force from the permanent magnet PM,so that the formation of the minute gap between the glass substrate GSand the mask MSK to be the main cause of the entrance of the protectionfilm into the frame region can be suppressed. However, in the relatedtechnology 2, as a side effect of embedding the permanent magnet PM inthe substrate loading unit SLU, the magnetic field from the permanentmagnet PM reaches the plasma PLS even in the state where the plasma PLSis generated. Accordingly, the adverse effect of the magnetic field actsas the Lorentz force on the charged particles constituting the plasmaPLS, resulting in the side effect that the film thickness distributionof the protection film formed over the glass substrate GS is disturbed.Namely, in the related technology 2, the formation of the minute gapbetween the glass substrate GS and the mask MSK can be suppressed by theuse of magnetic force, whereas the adverse effect due to the magneticfield acts on the plasma PLS, resulting in the side effect of thedisturbance in the film thickness distribution of the protection filmformed over the glass substrate GS.

<<Inevitability of Use of Plasma>>

Here, as a measure of preventing the side effect of the disturbance inthe film thickness distribution of the protection film due to theLorentz force acting on the charged particles constituting the plasma bythe magnetic field generated from the permanent magnet, it can bethought that the side effect may not be caused if the plasma is notused. Namely, it is conceivable that the side effect of the disturbancein the film thickness distribution of the protection film can beprevented without being adversely affected by the magnetic fieldgenerated from the permanent magnet when the atomic layer depositionmethod using no plasma is used as the film-forming method of forming theprotection film instead of the plasma atomic layer deposition methodusing plasma.

In this respect, in particular, in the process of forming the protectionfilm so as to cover the glass substrate having the organic EL elementformed therein, there is an inevitability of using the plasma atomiclayer deposition method. Namely, the organic EL element is weak at hightemperature, and thus it is difficult to heat the glass substrate havingthe organic EL element formed therein to high temperature. Further, inorder to form the high-quality protection film by the atomic layerdeposition method using no plasma, it is necessary to set thefilm-forming temperature to a high temperature, and when the protectionfilm is formed while setting the film-forming temperature to a lowtemperature inconsideration of the organic EL element, it is difficultto form the high-quality protection film. On the other hand, sinceplasma is used in the plasma atomic layer deposition method, thehigh-quality protection film can be formed even when the film-formingtemperature is set to a low temperature that does not affect the organicEL element.

As described above, in the process of forming the protection film so asto cover the glass substrate having the organic EL element formedtherein, there is an inevitability of using the plasma atomic layerdeposition method. Namely, as a measure of preventing the side effect ofthe disturbance in the film thickness distribution of the protectionfilm due to the Lorentz force acting on the charged particlesconstituting the plasma by the magnetic field generated from thepermanent magnet, there is no room to select the atomic layer depositionmethod using no plasma. Therefore, in order to solve the side effect ofthe disturbance in the film thickness distribution of the protectionfilm due to the Lorentz force acting on the charged particlesconstituting the plasma by the magnetic field generated from thepermanent magnet, a further contrivance is required.

<<Difficulty in Applying Related Technology 2>>

In addition, in the related technology 2, a contrivance of making themask from a magnetic substance and forcibly attracting the mask to theglass substrate by the magnetic force from the permanent magnet embeddedin the substrate loading unit is applied for suppressing the formationof the minute gap between the glass substrate and the mask to be themain cause of the entrance of the protection film into the frame region.In this respect, it is difficult to actually apply the relatedtechnology 2 to the manufacturing process of the protection film thatcovers the glass substrate having the organic EL element formed therein.

This will be described below. For example, although the organic ELelement is weak at high temperature, the film-forming temperature isabout 80 to 100° C. when the protection film that covers the glasssubstrate having the organic EL element formed therein is formed by theplasma atomic layer deposition method. This means that the substrateloading unit in which the permanent magnet is embedded is also heated toabout 80 to 100° C. This means that the temperature of about 80 to 100°C. is applied also to the permanent magnet embedded in the substrateloading unit.

Here, it is known that the permanent magnet loses the function as amagnet when it is heated to a high temperature. Therefore, it isdifficult to apply the idea of making the mask from a magnetic substanceand forcibly attracting the mask to the glass substrate by the magneticforce of the permanent magnet embedded in the substrate loading unit tothe process of forming the protection film that covers the glasssubstrate having the organic EL element formed therein by the plasmaatomic layer deposition method. This is because the permanent magnet isheated to a temperature of about 80 to 100° C. in this process, so thatthe permanent magnet becomes unable to exert the function as a magnet.Namely, although the idea of the related technology 2 seems useful fromthe viewpoint of suppressing the formation of the minute gap between theglass substrate and the mask to be the main cause of the entrance of theprotection film into the frame region, it is difficult to actually applythe idea to the process of forming the protection film that covers theglass substrate having the organic EL element formed therein by theplasma atomic layer deposition method, and a further contrivance isrequired.

Thus, in this embodiment, while using the idea of the related technology2 as a basic idea, a contrivance capable of being actually applied tothe process of forming the protection film that covers the glasssubstrate having the organic EL element formed therein by the plasmaatomic layer deposition method and capable of suppressing the sideeffect that appears in the related technology 2 is applied. Thetechnological idea according to this embodiment to which thiscontrivance is applied will be described.

<Plasma Atomic Layer Deposition Apparatus>

FIG. 23 is a diagram showing a schematic configuration in a processchamber of a plasma atomic layer deposition apparatus according to thisembodiment. In FIG. 23, the plasma atomic layer deposition apparatusaccording to this embodiment is configured to forma film over the glasssubstrate GS by using the mask MSK disposed over the glass substrate GSand made of a magnetic substance and the plasma generated above theglass substrate GS.

In particular, the plasma atomic layer deposition apparatus according tothis embodiment is configured to form a protection film that protects anorganic EL element. For example, the protection film that protects theorganic EL element is made of an insulating film such as a silicon oxidefilm, a silicon nitride film, a silicon oxynitride film, an aluminumoxide film or an aluminum oxynitride film. Therefore, the plasma atomiclayer deposition apparatus according to this embodiment includes a gassupply unit (not shown) connected to a process chamber, and can formvarious kinds of films typified by an aluminum oxide film and a siliconoxide film by changing source gas, reaction gas, and purge gasintroduced into the process chamber from the gas supply unit.

Next, as shown in FIG. 23, the plasma atomic layer deposition apparatusaccording to this embodiment includes the substrate loading unit SLUover which the glass substrate GS is loaded, and the substrate loadingunit SLU includes the stage ST and the susceptor SP disposed over thestage ST. Also, in the susceptor SP, the magnetic field generating unitMGU composed of an electromagnet EM is provided so as to be embedded inthe susceptor SP. Then, the glass substrate GS is loaded over thesusceptor SP.

Further, the plasma atomic layer deposition apparatus according to thisembodiment includes the upper electrode UE provided above the substrateloading unit SLU, a high frequency power source unit (not shown in FIG.23) connectable to the upper electrode UE, and a control unit CUelectrically connected to the magnetic field generating unit MGUcomposed of the electromagnet EM. At this time, the control unit CU isconfigured to control the generation and stop of the magnetic field fromthe magnetic field generating unit MGU and to control the supply andstop of the high frequency voltage to the upper electrode UE. Also, thecontrol unit CU is configured to be able to switch the generation andstop of the magnetic field from the magnetic field generating unit MGUduring the film-forming operation.

In the plasma atomic layer deposition apparatus configured in the mannerdescribed above, the control unit CU is configured to be able to stopthe generation of the magnetic field from the magnetic field generatingunit MGU during the period when the plasma is generated. In other words,the control unit CU is configured to be able to stop the generation ofthe magnetic field from the magnetic field generating unit MGU duringthe period when the high frequency voltage is supplied to the upperelectrode UE. In addition, the control unit CU is configured to be ableto generate the magnetic field from the magnetic field generating unitMGU during the period when the supply of the high frequency voltage tothe upper electrode UE is stopped.

<Film-Forming Method Using Plasma Atomic Layer Deposition Method>

In the manner described above, the plasma atomic layer depositionapparatus according to this embodiment is configured, and thefilm-forming method of forming the protection film that covers the glasssubstrate GS having the organic EL element formed therein by using theplasma atomic layer deposition apparatus thus configured will bedescribed below.

FIG. 23 is a schematic diagram showing a state in which source gas isintroduced into the process chamber of the plasma atomic layerdeposition apparatus according to this embodiment. In FIG. 23, thesubstrate loading unit SLU is provided in the process chamber in thisembodiment. This substrate loading unit SLU includes the stage ST andthe susceptor SP disposed over the stage ST, and the electromagnet EMfunctioning as the magnetic field generating unit MGU is embedded in thesusceptor SP. Further, the glass substrate GS having the organic ELelement formed therein is loaded over the susceptor SP. Also, as shownin FIG. 23, the mask MSK made of a magnetic substance is disposed overthe glass substrate GS. In addition, at the stage shown in FIG. 23, thecontrol unit CU of the plasma atomic layer deposition apparatusaccording to this embodiment controls to allow a current to flow to theelectromagnet EM. Consequently, the magnetic field is generated from theelectromagnet EM, and the mask MSK made of a magnetic substance isattracted to the electromagnet EM by the magnetic force based on themagnetic field. As a result, the adhesion between the mask MSK and theglass substrate GS is improved, and the minute gap is not presentbetween the mask MSK and the glass substrate GS.

Further, in the process chamber, the upper electrode UE is disposed atthe position facing the mask MSK, and the space sandwiched between themask MSK and the upper electrode UE serves as the film-forming space. Atthis time, at the stage shown in FIG. 23, the control unit CU of theplasma atomic layer deposition apparatus according to this embodimentcontrols so that the upper electrode UE and the high frequency powersource are in a non-connected state. As a result, at the stage shown inFIG. 23, no high frequency voltage is applied to the upper electrode UE,and no plasma is generated in the film-forming space.

Further, the source gas SG is introduced into the film-forming spacefrom the gas supply unit (not shown). The source gas is made of, forexample, trimethyl aluminum (TMA). At this time, since the minute gap isnot present between the mask MSK and the glass substrate GS in thisembodiment, the source gas SG does not enter between the glass substrateGS and the mask MSK.

Next, FIG. 24 is a schematic diagram showing a state in which purge gasis introduced into the process chamber of the plasma atomic layerdeposition apparatus according to this embodiment. At this time, purgegas made of, for example, nitrogen gas is supplied into the processchamber from the gas supply unit (not shown). Consequently, the sourcegas SG remaining in the process space is exhausted from the processspace. Even at this stage, the control unit CU controls so as to allow acurrent to flow to the electromagnet EM. Thus, the electromagnet EMcontinues to generate the magnetic field, and the state in which themask MSK made of a magnetic substance is attracted to the electromagnetEM by the magnetic force based on the magnetic field is maintained. As aresult, the adhesion between the mask MSK and the glass substrate GS isimproved, and the minute gap is not present between the mask MSK and theglass substrate GS.

Note that, at the stage shown in FIG. 24, the control unit CU of theplasma atomic layer deposition apparatus according to this embodimentcontrols so that the upper electrode UE and the high frequency powersource are in a non-connected state. As a result, at the stage shown inFIG. 24, no high frequency voltage is applied to the upper electrode UE,and no plasma is generated in the film-forming space.

Subsequently, FIG. 25 is a schematic diagram showing a state in whichreaction gas is introduced into the process chamber of the plasma atomiclayer deposition apparatus according to this embodiment. At this time,the reaction gas AG made of, for example, oxygen gas is supplied intothe process chamber from the gas supply unit (not shown). Even at thisstage, the control unit CU still controls so as to allow a current toflow to the electromagnet EM. Thus, the electromagnet EM continues togenerate the magnetic field, and the state in which the mask MSK made ofa magnetic substance is attracted to the electromagnet EM by themagnetic force based on the magnetic field is maintained. As a result,the adhesion between the mask MSK and the glass substrate GS isimproved, and the minute gap is not present between the mask MSK and theglass substrate GS. Note that, at the stage shown in FIG. 25, thecontrol unit CU of the plasma atomic layer deposition apparatusaccording to this embodiment continues to control so that the upperelectrode UE and the high frequency power source are in a non-connectedstate. As a result, at the stage shown in FIG. 25, no high frequencyvoltage is applied to the upper electrode UE, and no plasma is generatedin the film-forming space.

Next, FIG. 26 is a schematic diagram showing a state in which plasma isgenerated in the process chamber of the plasma atomic layer depositionapparatus according to this embodiment. At this time, the reaction gasAG made of, for example, oxygen gas is supplied into the process chamberfrom the gas supply unit (not shown). At this stage, the control unit CUcontrols so as to block the current supply to the electromagnet EM.Consequently, the generation of the magnetic field from theelectromagnet EM is stopped. As a result, the attraction force does notact on the mask MSK made of a magnetic substance, and the minute gap ispresent between the mask MSK and the glass substrate GS. On the otherhand, at the stage shown in FIG. 26, the control unit CU of the plasmaatomic layer deposition apparatus according to this embodiment controlsso that the upper electrode UE and the high frequency power source RFSare in a connected state. Consequently, the high frequency voltage isapplied to the upper electrode UE from the high frequency power sourceRFS. As a result, the plasma PLS containing radicals (active species)and charged particles is generated in the film-forming space. Then, theadsorption layer formed over the glass substrate GS by introducing thesource gas SG and the reaction gas AG converted into plasma react witheach other by the plasma PLS, so that the protection film made of, forexample, an aluminum oxide film is formed so as to cover the organic ELelement formed in the glass substrate GS. Namely, the protection film isformed in the region of the glass substrate GS exposed from the openingregion of the mask MSK. At this time, in this embodiment, the minute gapis present between the mask MSK and the glass substrate GS. Therefore,it is conceivable that the reaction gas converted into plasma enters theminute gap. However, in this embodiment, for example, the minute gap isnot present between the mask MSK and the glass substrate GS in the stepof supplying the source gas SG shown in FIG. 23. As a result, since theadsorption layer based on the source gas SG is not formed in the minutegap, no chemical reaction occurs even if the reaction gas converted intoplasma enters the minute gap. Accordingly, the protection film is notformed in the minute gap between the mask MSK and the glass substrate GSshown in FIG. 26.

Further, as shown in FIG. 26, at the stage in which the plasma PLS isgenerated, the generation of the magnetic field from the electromagnetEM is stopped. Therefore, according to this embodiment, the Lorentzforce does not act on the charged particles constituting the plasma PLS,and the disturbance in the film thickness distribution of the protectionfilm due to the Lorentz force acting on the charged particles can besuppressed.

Subsequently, FIG. 27 is a schematic diagram showing a state in whichpurge gas is introduced into the process chamber of the plasma atomiclayer deposition apparatus according to this embodiment. At this time,the purge gas made of, for example, nitrogen gas is supplied into theprocess chamber from the gas supply unit (not shown). Consequently, thereaction gas AG remaining in the process space is exhausted from theprocess space. At this stage, the control unit CU controls to allow acurrent to flow to the electromagnet EM again. Consequently, theelectromagnet EM starts to generate the magnetic field, and the mask MSKmade of a magnetic substance is attracted to the electromagnet EM by themagnetic force based on the magnetic field. As a result, the adhesionbetween the mask MSK and the glass substrate GS is improved, and theminute gap ceases to be present between the mask MSK and the glasssubstrate GS.

Note that, at the stage shown in FIG. 27, the control unit CU of theplasma atomic layer deposition apparatus according to this embodimentcontrols so that the upper electrode UE and the high frequency powersource are in a non-connected state. Consequently, at the stage shown inFIG. 27, the application of the high frequency voltage to the upperelectrode UE is stopped. As a result, the plasma PLS generated in thefilm-forming space disappears.

In the manner described above, in this embodiment, the protection filmmade of, for example, an aluminum oxide film can be formed so as tocover the organic EL element formed in the glass substrate GS by theplasma atomic layer deposition method using the mask MSK.

The film-forming method according to this embodiment is the film-formingmethod using the plasma atomic layer deposition apparatus including thesubstrate loading unit SLU having the magnetic field generating unitMGU. Also, the film-forming method according to this embodiment includes(a) “a step of loading the substrate over the substrate loading unitSLU”, (b) “a step of disposing the mask MSK made of a magnetic substanceover the substrate”, and (c) “after the step (b), a step of generatingthe magnetic field from the magnetic field generating unit MGU”.

Next, the film-forming method according to this embodiment includes (d)“after the step (c), a step of supplying the source gas SG to thesubstrate”, (e) “a step of stopping the supply of the source gas SG”,and (f) “after the step (e), a step of stopping the generation of themagnetic field from the magnetic field generating unit MGU”.

Further, the film-forming method according to this embodiment includes(g) “after the step (e), a step of supplying the reaction gas AG to thesubstrate” and (h) “after the step (f) and the step (g), a step ofgenerating the plasma PLS above the substrate”.

At this time, for example, the magnetic field generating unit MGUincludes the electromagnet EM, and the magnetic field is generated fromthe magnetic field generating unit MGU by allowing a current to flow tothe electromagnet EM in the step (c).

Note that the substrate contains a material having translucency tovisible light. Specifically, the substrate can be configured to containa glass material or contain a resin material, and the substrate may be adeformable flexible substrate.

<Characteristic Point in this Embodiment>

Subsequently, the characteristic point in this embodiment will bedescribed. The characteristic point in this embodiment is that thegeneration and stop of the magnetic field from the magnetic fieldgenerating unit is switched during the film-forming process.Consequently, for example, the generation of the magnetic field from themagnetic field generating unit can be stopped during the period when theplasma process is performed. As a result, according to this embodiment,it is possible to prevent the Lorentz force based on the magnetic fieldfrom acting on the charged particles constituting the plasma, so thatthe disturbance in the film thickness distribution of the protectionfilm can be suppressed. On the other hand, during the period of thefilm-forming process in which the plasma process is not performed, themagnetic field is generated from the magnetic field generating unit.Consequently, the mask made of a magnetic substance is attracted to themagnetic field generating unit, and as a result, the adhesion betweenthe glass substrate loaded over the substrate loading unit in which themagnetic field generating unit is embedded and the mask disposed overthe glass substrate can be improved. Accordingly, since the formation ofthe minute gap between the mask and the glass substrate can beprevented, the entrance of the protection film into the minute gap canbe suppressed.

As described above, according to this embodiment, by adopting thecharacteristic point that the generation and stop of the magnetic fieldfrom the magnetic field generating unit is switched during thefilm-forming process, it is possible to achieve both of the suppressionof the entrance of the protection film into the frame region coveredwith the cover region of the mask and the prevention of the disturbancein the film thickness distribution of the protection film due to theadverse effect on the plasma by the magnetic field.

Namely, when the generation of the magnetic field from the magneticfield generating unit is continued over the entire period of thefilm-forming process, the adverse effect of the magnetic field acts asthe Lorentz force on the charged particles constituting the plasma alsoduring the period when the plasma process is performed. In this case,the distribution of the charged particles in the plasma is disturbed bythe Lorentz force, resulting in the disturbance in the film thicknessdistribution of the protection film. On the other hand, when thegeneration of the magnetic field by the magnetic field generating unitis not used, the minute gap is formed between the mask and the glasssubstrate, and the entrance of the protection film occurs in the minutegap. Therefore, the idea (characteristic point) of switching thegeneration and stop of the magnetic field from the magnetic fieldgenerating unit during the film-forming process is extremely useful fromthe viewpoint of solving the problem described above.

In addition, in this embodiment, in order to embody the idea ofswitching the generation and stop of the magnetic field from themagnetic field generating unit during the film-forming process, themagnetic field generating unit is composed of the electromagnet. This isbecause, since the magnetic field can be generated by allowing a currentto flow to the electromagnet and no magnetic field is generated when nocurrent flows to the electromagnet, the generation and stop of themagnetic field from the electromagnet (magnetic field generating unit)can be switched by controlling the on and off of the current flowing tothe electromagnet. On the other hand, since the permanent magnet alwaysgenerates the magnetic field, it is not possible to embody the idea ofswitching the generation and stop of the magnetic field. Therefore, itcan be seen that the idea of switching the generation and stop of themagnetic field from the magnetic field generating unit during thefilm-forming process can be easily realized by composing the magneticfield generating unit from the electromagnet.

Further, when the magnetic field generating unit is composed of theelectromagnet, the following advantage can be obtained. For example,although the organic EL element is weak at high temperature, thefilm-forming temperature is about 80 to 100° C. when the protection filmthat covers the glass substrate having the organic EL element formedtherein is formed by the plasma atomic layer deposition method. At thistime, when the magnetic field generating unit is composed of thepermanent magnet, the substrate loading unit in which the permanentmagnet is embedded is also heated to about 80 to 100° C., and this meansthat the temperature of about 80 to 100° C. is applied also to thepermanent magnet embedded in the substrate loading unit.

Here, it is known that the permanent magnet loses the function as amagnet when it is heated to a high temperature. Therefore, it isdifficult to apply the idea of making the mask from a magnetic substanceand forcibly attracting the mask to the glass substrate by the magneticforce of the permanent magnet embedded in the substrate loading unit tothe process of forming the protection film that covers the glasssubstrate having the organic EL element formed therein by the plasmaatomic layer deposition method. This is because the permanent magnet isheated to a temperature of about 80 to 100° C. in this process, so thatthe permanent magnet becomes unable to exert the function as a magnet.Namely, although the idea of forcibly attracting the mask to the glasssubstrate by the magnetic force from the permanent magnet embedded inthe substrate loading unit seems useful from the viewpoint ofsuppressing the formation of the minute gap between the glass substrateand the mask to be the main cause of the entrance of the protection filminto the frame region, it is difficult to actually apply the idea to theprocess of forming the protection film that covers the glass substratehaving the organic EL element formed therein by the plasma atomic layerdeposition method.

On the other hand, in this embodiment, the magnetic field generatingunit is composed of the electromagnet. In this case, unlike thepermanent magnet, the electromagnet does not lose the function as amagnet even when it is exposed to a high temperature. Namely, even whenthe electromagnet is put in a high-temperature state, the magnetic fieldcan be generated from the electromagnet by allowing a current to flow tothe electromagnet. As described above, only after the magnetic fieldgenerating unit is composed of the electromagnet, the idea of making themask from a magnetic substance and forcibly attracting the mask to theglass substrate by the magnetic force from the magnetic field generatingunit embedded in the substrate loading unit can be applied to theprocess of forming the protection film that covers the glass substratehaving the organic EL element formed therein by the plasma atomic layerdeposition method. Therefore, when the magnetic field generating unit iscomposed of the electromagnet, it is possible to obtain the advantagethat the configuration in which the mask is forcibly attracted to theglass substrate by the magnetic force can be effectively applied to theprocess including the heat treatment as with the process of forming theprotection film that covers the glass substrate having the organic ELelement formed therein by the plasma atomic layer deposition method.

Further, by composing the magnetic field generating unit from theelectromagnet, it is also possible to obtain the advantage that themagnitude of the magnetic field that forcibly attracts the mask to theglass substrate can be adjusted. This is because the magnitude of themagnetic field generated from the electromagnet changes depending on themagnitude of the current flowing to the electromagnet. Therefore, forexample, in the case where the minute gap is formed between the mask andthe glass substrate and the entrance of the protection film into theminute gap (entrance of the protection film into the frame regioncovered with the mask) becomes apparent even when the current flowing tothe electromagnet is set to a first current value, the magnetic forcethat attracts the mask can be increased by changing the current flowingto the electromagnet to a second current value larger than the firstcurrent value. In this manner, the formation of the minute gap betweenthe mask and the glass substrate can be suppressed without changing theconfiguration of the electromagnet, so that it is possible to obtain theadvantage of being able to flexibly cope with the entrance of theprotection film into the minute gap (entrance of the protection filminto the frame region covered with the mask).

<Verification of Effect of this Embodiment>

Finally, the remarkable effect achieved by the technological idea ofthis embodiment will be described. An aluminum oxynitride (AlON) filmfunctioning as a protection film is formed over a glass substrate of 370mm×470 mm by using the plasma atomic layer deposition apparatusaccording to this embodiment. At this time, trimethyl aluminum is usedas source gas, and oxygen gas and nitrogen gas are used as reaction gas.The number of cycles (number of repetitions) of the plasma atomic layerdeposition method is set to 620 so that the protection film having athickness of 100 nm is formed over the glass substrate exposed from theopening region of the mask. Under the film-forming conditions describedabove, the thickness of the protection film is measured at eightmeasurement points A to H shown in FIG. 28.

FIG. 28 is a diagram schematically showing the points A to H which aremeasurement points. As shown in FIG. 28, the mask MSK has the coverregion CVR and the opening regions OPR formed therein. The points A to Dare each located at the position away from an edge of the opening regionOPR toward the cover region CVR by 300 km, and the points E to H areeach located at the position away from the edge of the opening regionOPR toward an inside of the opening region OPR by 300 μm.

FIG. 29 is a graph showing measurement results of the thickness of theprotection film at the measurement points indicated by the points A to Hof FIG. 28. In FIG. 29, the graph on the left side corresponds to thisembodiment, that is, the configuration in which the generation and stopof the magnetic field from the magnetic field generating unit isswitched so that the generation of the magnetic field from the magneticfield generating unit is stopped during the period when the plasmaprocess is performed and the magnetic field is generated from themagnetic field generating unit during the period of the film-formingprocess when the plasma process is not performed.

Meanwhile, the graph at the center corresponds to the related technology1 in which the magnetic field generating unit is not provided, that is,the configuration in which the generation of the magnetic field from themagnetic field generating unit is stopped over the entire period of thefilm-forming process. In addition, the graph on the right sidecorresponds to the related technology 2, that is, the configuration inwhich the magnetic field is generated from the magnetic field generatingunit over the entire period of the film-forming process.

As shown in FIG. 29 (graph at the center), it can be seen that theprotection film is formed considerably at the points A to D, while theprotection film is formed with a substantially uniform thickness at thepoints E to H in the related technology 1. The results at the points Ato D indicate that the protection film enters and is formed over theglass substrate covered with the cover region of the mask. On the otherhand, the results at the points E to H indicate that the generation ofthe magnetic field is not present at the time of generating the plasma,and thus the variation in film thickness (disturbance in film thicknessdistribution) of the protection film formed over the glass substrateexposed from the opening regions of the mask does not occur.Consequently, it can be seen that the disturbance in the film thicknessdistribution of the protection film due to the adverse effect on theplasma by the magnetic field can be prevented, but the entrance of theprotection film into the frame region covered with the cover region ofthe mask cannot be suppressed in the related technology 1.

As shown in FIG. 29 (graph on the right side), it can be seen that theprotection film is hardly formed at the points A to D, while theprotection film is formed with a considerably large variation in filmthickness at the points E to H in the related technology 2. The resultsat the points A to D indicate that the protection film does not enterand is not formed over the glass substrate covered with the cover regionof the mask. On the other hand, the results at the points E to Hindicate that the generation of the magnetic field is present at thetime of generating the plasma, and thus, the variation in film thickness(disturbance in film thickness distribution) of the protection filmformed over the glass substrate exposed from the opening regions of themask occurs. Consequently, it can be seen that the entrance of theprotection film into the frame region covered with the cover region ofthe mask can be suppressed, but the disturbance in the film thicknessdistribution of the protection film due to the adverse effect on theplasma by the magnetic field cannot be prevented in the relatedtechnology 2.

On the other hand, as shown in FIG. 29 (graph on the left side), it canbe seen that the protection film is hardly formed at the points A to D,while the protection film is formed with a substantially uniform filmthickness at the points E to H in this embodiment. The results at thepoints A to D indicate that the protection film does not enter and isnot formed over the glass substrate covered with the cover region of themask. On the other hand, the results at the points E to H indicate thatthe generation of the magnetic field is stopped at the time ofgenerating the plasma, and thus, the variation in film thickness(disturbance in film thickness distribution) of the protection filmformed over the glass substrate exposed from the opening regions of themask does not occur. Consequently, it can be said that this verifiesthat the technological idea according to this embodiment makes itpossible to obtain the remarkable effect of being able to achieve bothof the suppression of the entrance of the protection film into the frameregion covered with the cover region of the mask and the prevention ofthe disturbance in the film thickness distribution of the protectionfilm due to the adverse effect on the plasma by the magnetic field.Namely, it can be seen that the remarkable effect that cannot beobtained by the related technology 1 and the related technology 2 can beobtained by the technological idea according to this embodiment.

In the foregoing, the invention made by the inventors of the presentinvention has been concretely described based on the embodiments.However, it is needless to say that the present invention is not limitedto the foregoing embodiments and various modifications can be madewithin the scope of the present invention.

REFERENCE SIGNS LIST

-   -   AG: reaction gas    -   CU: control unit    -   EM: electromagnet    -   GS: glass substrate    -   MGU: magnetic field generating unit    -   MSK: mask    -   PF: protection film    -   PLS: plasma    -   RFS: high frequency power source    -   SG: source gas    -   SLU: substrate loading unit

1-15. (canceled)
 16. A plasma atomic layer deposition apparatus thatforms a film over a substrate by using a mask made of a magneticsubstance disposed over the substrate and plasma generated above thesubstrate, the apparatus comprising: a substrate loading unit over whichthe substrate is loaded; an upper electrode provided above the substrateloading unit; a high frequency power source unit connectable to theupper electrode; a magnetic field generating unit provided in thesubstrate loading unit; and a control unit that controls generation andstop of a magnetic field from the magnetic field generating unit andcontrols supply and stop of a high frequency voltage to the upperelectrode, wherein the control unit switches the generation and stop ofthe magnetic field from the magnetic field generating unit during afilm-forming process.
 17. The plasma atomic layer deposition apparatusaccording to claim 16, wherein the control unit stops the generation ofthe magnetic field from the magnetic field generating unit during aperiod when the plasma is generated.
 18. The plasma atomic layerdeposition apparatus according to claim 16, wherein the control unitstops the generation of the magnetic field from the magnetic fieldgenerating unit during a period when the high frequency voltage issupplied to the upper electrode.
 19. The plasma atomic layer depositionapparatus according to claim 18, wherein the control unit generates themagnetic field from the magnetic field generating unit during a periodwhen the supply of the high frequency voltage to the upper electrode isstopped.
 20. The plasma atomic layer deposition apparatus according toclaim 16, wherein the film is a protection film that protects an organicEL element.